Exhaust gas driven turbine



mg., M193? s.; R. PUFFER EXHAUST @As DRIVEN TURBINE Fild' Aug. 51, 1934Trifgl.

Yam/faro Inventor: Y Samuel R. PuFFe; bg #my His 'Attorney y PatentedAug. 10, 1937 PATENT OFFICE EXHAUST GAS DRIVEN TURBINE Samuel R. Puffer,Saugus, Mass., assigner to General Electric Company, a corporation ofNew York Application August 31,

3 Claims.

The present invention relates to exhaust gas driven turbines. Theinvention is especially applicabl to exhaust gas driven turbinesuperchargers for airplane engines and it is partic- 5` ularlyillustrated and described in connection with such a supercharger. It isto be understood, however, that the invention is not limited theretonecessarily but may be utilized wherever found applicable.

Due to the high temperature of the exhaust gases from an internalcombustion engine, it is necessary to provide cooling means for the gasturbine of a turbine driven supercharger and the object of the presentinvention is to provide an l5 improved construction and arrangement` foreiecting cooling of the gas turbine and especially the bearing adjacentto the turbine wheel.

For a consideration vof` what I believe to be novel and my invention,attention is directed to the following description andthe claimsappended thereto.

In the drawing, Fig. 1 is a sectional view of a gas turbine embodying myinvention; Fig. 2 is an outline of an airplane having an engine provided25 with a gas turbine driven supercharger and illustrating anarrangement for supplying air for cooling purposes, and Fig. 3 shows amodification.

Referring to the drawing, I indicates an airplane provided with aninternal combustion engine 2 which drives a propellerA 3 andwhich isenclosed in a housing or casing 4. The engine is providedA with asupercharger comprising a turbine driven by `exhaust gases from theengine, the turbine in turn driving a, centrifugal comvpresser forsupplying compressed air to the engine intake manifold.. Usually, theair is supplied to the manifold in advance-of the carburetor so that theair passes through the carburetor on its way to the manifold. Thepresent invention has to do particularly with the turbine and itsadjacent bearing and accordingly the centrifugal compressor is notspecifically illustrated in the drawing.

Referring to Fig. l, 5 indicates a xed support or frame carried by astationary part of the engine or airplane structure and provided with anupper bearing and a lower bearing 1. The upper bearing has a lining Sprovided with an oil groove 9 to which is connected an oil supply pipei8. Formed integral with the bearing lining 8 is a flange Il whichiorrns a step bearing.

The lower bearing l is provided with a lining I2 having an oil groove 33with which is connected an oil supply pipe i3. Also, bearing 'l is 55provided with cooling fins it.

1934, Serial No. 742,357

Mounted in bearings 6 and I is a shaft I6 on the upper end of which isfixed a beveled gear I1 which rests on bearing flange II and serves as asupport for the shaft. Beveled gear wheel Il, through suitableconnections, drives the impeller of centrifugal compressor (not shown).Shaft I6 is preferably made hollow in order to reduce its weight. i

VFixed to the lower end of shaft I6 is a turbine wheel I8 provided witha row of buckets I9. The turbine wheel is xed to a flange. on the lowerend of shaft I6 by studs 20 and is spaced away from the lower side ofbearing l. The turbine wheel is directly in the open, it being notprovided with a` casing of any kind.

Above the ring of buckets I9 is located a nozzle ring 2| having nozzlesthrough which gas is directed to the ,buckets of the turbine wheel. Thenozzle ring is 'carried by an annular nozzle box 22 to which areconnected pipes 23 which convey exhaust gases from the engine cylindersto the nozzle box. The nozzle box is provided also with a dischargeconduit 24 in which is located a waste valve 25. The waste valve isutilized to control the supply of exhaust gases to the turbine wheel.When the valve is open, exhaust gases discharge for the most partdirectly to the atmosphere. As the valve is closed, more and more of thegases are directed through the nozzles to the turbine wheel, all thegases being so directed when the valve is entirely closed. This is aknown arrangement for controlling the supply of exhaust gases to a gasdriven supercharger.

Surrounding the lower end of bearing 1 are walls which form an annularoil chamber 2E 35 which at the right hand side of the drawing isenlarged to provide a sump 2'1. Oil discharged through the lower end ofbearing I nds its way to oil chamber 26 and sump 2l through an annularspace 28 which is defined by the lower flanged end of bearing lining l2and an oil deflector ring 29 carried by shaft I6 and provided with a lipwhich depends into chamber 26 adjacent to the upper edgeof the annularwall 36 of the `oil chamber. Deflector ring 29 serves to divert oilleaking from the lower end of bearing 7, into oil chamber 26.Communicating with the lower end of sump 27 is a passage 3l to which isconnected a discharge pipe 32. Oil discharged 50 from the lower end ofupper bearing 5 nds its Way to a sump 33 at the lower end of casing 5 towhich is connected a discharge pipe 35. Pipes 32 and 3 are connected bya pipe 35 to a suitable pump (not shown) for pumping oil from sumps haw@v 2l and 33 and returning it to the main oil supply a better cooling oithe bearing. Such an arrangetanlt.

bearing 'l in spaced relation thereto is an annular wall 36 connected atits upper and lower ends to casing and nozzle ring 2i respectively, andforming a support for the nozzle ring. Wall 36 defines an air coolingchamber 36 which surrounds the lower bearing Chamber 3Gk is closed atits lower end by turbine wheel i8. Or otherwise considered. the uppersurface of turbine wheel Il Ls exposed directly to the air coolingchamber. Nozzle box 22 surrounds the air cooling chamber. Air issupplied to the air cooling chamber by a conduit 3l which projects outthrough housing, I and points forwardly into the slip stream. It servesto take air from the atmosphere and discharge it to the air coolingchamber. Inside the aircoolim chamber is a wall 39 which serves todirect the air to the bearing and also toward the top surface of theturbine wheel. On the side of the air cooling chamber opposite conduit38 is a discharge conduit Il through which air is discharged from thecooling chamber. The air from conduit I8 may be discharged directly tothe atmosphere or it may be utilized as a partial or complete air supplyfor the engine intake manifold. It may be utilized with advantage as anair supply for the engine in cold weather as it is heated dueto itspassage over the bearing and turbine wheel.

In Fig. 1 of the drawing, conduit 4l is shown as discharging to thecarburetor which in turn supplies mixture to the intake manifold. Thecarburetor'is indicated diagrammatically at Ill. In Fig. 2, conduit 40is shown as discharging to the atmosphere, it being bent so that itsdischarge end faces rearwardly to obtain the benefit of the suctioneiect of the air flowing past it when the airplane is moving.

With the above described arrangement, when the airplane is moving, airBows through conduit 38 to the cooling chamber defined by wall 3E. Theair is directed over the lower bearing 1, the lower end of shaft I6, theoil chamber 2i, and the sump 21 effecting cooling of. these parts. Also,it is directed across the surface of the turbine wheel. 'I'he bearing Iis spaced somewhat from the turbine wheel so as to provide an air spacebetween it and the turbine wheel. Also, the turbine wheel when in.operation acts as a pump and effects a ow of air along its uppersurface, the air being discharged into the annular space 42 between therim of the wheel and the outer face -oi? the nozzle ring. This serves toconvey heat away from the upper surface of the turbine wheel and toprovide continuously a moving layer of air between the upper surface ofthe turbine wheel and the lower bearing. By this arrangement, I amenabled to keep the bearing cool enough so that it may be properlylubricated and, at the same time, I cool the turbine wheel.

In some instances, it may be found to be not desirable or necessary tocool the turbine wheel in conjunction with the cooling of the bearing.In such instances, I preferably provide a heat resisting shield betweenthe bearing and the turbine wheel for protecting the bearing fromradiant heat from the turbine wheel. This effects ment is shown in Fig.3 wherein 43 indicates a Shield located directly above the turbine wheeii3 and extending from the inner side of the nozzle ring 2l to the lowerend of shaft i6, the shield being in the form of a disc having a centraiopening through which shaft it projects. The shield may be formed toadvantage from upper and lower metal plates or discs M and 45 having alayer of suitable heat insulating material 4l between them, the platesbeing fastened together by rivets 41. Otherwise the arrangement shown inFig. 3 may be the same as that shown in Figs. 1 and 2.

With this arrangement, the shield serves to direct the air from wall l!toward the shaft and bearing and protects the bearing from radiant heatfrom the turbine wheel.

WhatIclaimasnewand desiretosecureby Letters Patent of the United States,is:

1. In combination, a gas driven turbine comprising a bearing, a shaft inthe bearing, said shaft having an overhung portion, a turbine wheelcarried by the overhung shaft portion. a wall completely surrounding thebearing to define a cooling chamber for the bearing and the turbinewheel, an end of the cooling chamber being formed by one side of theturbine wheel. the other side of the turbine wheel being entirelyexposed to the atmosphere, a nozzle box outside said wall for directinggases to the turbine wheel, and means for eecting flow of cooling airthrough said chamber, and means for conveying air from the coolingchamber toan engine.

2. In a gas turbine drive for airplane superchargers, the combination ofa vertical shaft having a lower end withA a ange, a gas turbineincluding a bucket wheel .having a central portion secured to theflange, a support, a bearing for an intermediate portionof the shaftsecured to the support, means for lubricating the bearing, the shaftbeing hollow and said bearing being spaced from the wheel to reduce thetransferA of heat from the wheel to the bearing and thereby to assureproper lubrication of the bearing, means for cooling a Aportion of thebearing adjacent the wheel comprising a chamber having a wall completelysurrounding the bearing and the lower shaft portion and a lower walldefined by a central portion of the turbine wheel and an upper walldened by said support, and means for forcing cooling air through saidchamber.

3. In a gas turbine drive for airplane superchargers, the combination ofa vertical shaft having a lower end with a flange, a` gas turbineincluding a bucket wheel having a central portion secured to the flange,a support, a bearing for an intermediate portion of the shaft secured tothe support, means for lubricating the bearing, said bearing beingconsiderably spaced from the wheel to reduce the transfer of heat fromthe wheel to the bearing and thereby to assune proper lubrication of thebearing, and means for cooling at least the portion of the bearingadjacent the wheel comprising a chamber having Walls formed partly bythe bearing and one side of the turbine wheel, said chamber having inletand outlet openings to permit ow of cooling medium therethrough.

SAMUEL R. PUFFER.

